86 AMERICAN WHEAT AND CORN. 



that is, of great or of limited activity of accumulation of constituents by 

 the plants; hence the withdrawal of constituents for seed-formation will 

 leave very various amounts of migratory matters in the straw. 



3. Taking high weight per bushel of the grain as a fairly good indi- 

 cation of high quality, and vice versa, there was with each condition 

 of manuring a general and marked but not uniform tendency to low 

 proportions of nitrogen, of total mineral constituents (ash), and of indi- 

 vidual ash constituents, in the dry substance of the grain of the seasons 

 of higher quality ; that is, the higher quality of the grain is associated 

 with the greater accumulation of the non-nitrogenous matters (carbo- 

 hydrates) in proportion to the nitrogen and to the mineral constituents 

 which have been stored up. 



4. Per 1,000 dry substance of the grain there is with each condition as 

 to manuring much greater uniformity in the amount, and a rather lower 

 average amount of potash in the eight better than in the eight worse 

 seasons. Yet it is in a very unfavorable season that there was actually 

 the lowest, and in the worst season of the sixteen that there was actually 

 the highest proportion of potash in the dry substance of the grain ; that 

 is, the very different results are obtained under defective but very dif- 

 ferent conditions of development and maturation. 



5. Per 1,000 dry substance of the grain there is under each of the three 

 conditions as to manuring a lower average amount of phosphoric acid 

 over the eight better seasons, and it is lower in individual seasons of 

 high quality, still there is a wider range than among the eight infe- 

 rior seasons and wider than in the case of the potash. In the case of 

 the farm yard manure-plot the lower proportion of phosphoric acid in 

 the better seasons cannot be due to exhaustion, but to enhanced pro- 

 duction of organic substance. The average proportion of phosphoric 

 acid to organic substance is, however, lower without manure than with 

 farm-yard manure, and lower still with ammonium salts alone, in which 

 case there is very abnormal mineral exhaustion. 



G. The details illustrate in a striking manner the greater influence of 

 season than of manuring on the proportion of the ash constituents to 

 the organic substance of the grain. With normal maturation it is, 

 under otherwise comparable conditions, nearly uniform with different 

 conditions as to manuring; and deviations from normal mineral com- 

 position are associated with deviations from normal development of the 

 organic substance. 



7. The percentage of silica in the dry substance of the straw is lower 

 in the seasons of more favorable maturation. In fact, stiffness of straw 

 depends on favorable development of the woody substance, by the in- 

 crease of which the proportion of the accumulated silica to the organic 

 substance is reduced. 



8. Excluding the ferric oxide and the silica, and calculating the 

 whole of the phosphoric acid, as tribasic, the grain ashes show more 

 than one and a half times as much acid as base; and even calculating 



